THESIS
2018
xviii, 320 pages : illustrations (some color) ; 30 cm
Abstract
Marine picocyanobacterium Prochlorococcus contributes to a vital proportion of the global
primary production, especially in the nutrient-limited oligotrophic oceans. Cyanophages
that infect Prochlorococcus redirect the intracellular metabolism of their cyanobacterial
host, releasing a variety of dissolved organic matter (DOM) from the lysed cells, eventually
affecting the global biogeochemical cycling. This thesis presents studies on the host-phage
interactions of the marine cyanobacterium Prochlorococcus, combining approaches from
omics-techniques, as well as physiological and biochemical assays. Analysis of the within-host proteomes during phage infection is essential for revealing the molecular dynamics of
host-phage interactions. As a consequence, we have conducted quantitati...[
Read more ]
Marine picocyanobacterium Prochlorococcus contributes to a vital proportion of the global
primary production, especially in the nutrient-limited oligotrophic oceans. Cyanophages
that infect Prochlorococcus redirect the intracellular metabolism of their cyanobacterial
host, releasing a variety of dissolved organic matter (DOM) from the lysed cells, eventually
affecting the global biogeochemical cycling. This thesis presents studies on the host-phage
interactions of the marine cyanobacterium Prochlorococcus, combining approaches from
omics-techniques, as well as physiological and biochemical assays. Analysis of the within-host proteomes during phage infection is essential for revealing the molecular dynamics of
host-phage interactions. As a consequence, we have conducted quantitative proteomics in
two sets of relatively well-defined host-phage systems—the cyanopodovirus P-SSP7 and
cyanomyovirus P-HM2 both infecting their host Prochlorococcus MED4. This work has
been first time characterising the quantitative proteomics during infection of Prochlorococcus by marine cyanophages, which provides further insight into the infection dynamics and mechanism on both translational and post-translational level. Meanwhile, the lysis-induced phytoplankton-released DOM is important for the marine food web because it
supports the growth of heterotrophic microorganisms. However, the impact of viral DOM
on the uninfected phytoplankton remains largely unknown. We therefore examined the
cyanobacterial responses towards viral lysis products. First, we have determined the elemental concentrations and amino acid compositions of the phytoplankton-derived DOM. Employing transcriptomic sequencing and biochemical assays, DOM-responsive genes and metabolism of the host Prochlorococcus have been identified and further validated. Collectively, the combined work presented herein has advanced the understandings of host-phage interactions of marine cyanobacterium Prochlorococcus, linking the infection dynamics
with molecular basis on various levels.
Post a Comment